The present invention relates to use of an internet-based system for determining a vehicle""s fuel efficiency (e.g., gas mileage).
The Environmental Protection Agency (EPA) requires vehicle manufacturers to install on-board diagnostics (e.g., microcontrollers and sensors, called xe2x80x98OBD-II systemsxe2x80x99) for monitoring light-duty automobiles and trucks beginning with model year 1996. OBD-II systems monitor the vehicle""s electrical, mechanical, and emissions systems and generate data that are processed by a vehicle""s engine control unit (ECU) to detect malfunctions or deterioration in the vehicle""s performance. Most ECUs transmit status and diagnostic information over a shared, standardized electronic buss in the vehicle. The buss effectively functions as an on-board computer network with many processors, each of which transmits and receives data.
Sensors that monitor the vehicle""s engine functions (e.g., spark controller, fuel controller) and power train (e.g., engine, transmission systems) generate data that pass across the buss. Such data are typically stored in random-access memory in the ECU and include parameters such as vehicle speed (VSS), engine speed (RPM), engine load (LOAD), and mass air flow (MAF). Some vehicles (e.g., certain 2001 Toyota Camrys) lack a MAF sensor, in which case the MAF datum is not available from the ECU. Nearly all OBD-compliant vehicles, however, report VSS, RPM, and LOAD. When present, these and other data are made available through a standardized, serial 16-cavity connector referred to herein as an xe2x80x98OBD-II connectorxe2x80x99. The OBD-II connector is in electrical communication with the ECU and typically lies underneath the vehicle""s dashboard. A diagnostic tool called a xe2x80x98scan toolxe2x80x99 typically connects to the OBD-II connector and downloads diagnostic data when a vehicle is brought in for service.
It is an object of the present invention to provide a wireless, internet-based system for monitoring a vehicle""s fuel efficiency. Specifically, it is an object of the invention to access data from a vehicle while it is in use, transmit a data set wirelessly through a network and to a website, and analyze the data set with a host computer system to determine the vehicle""s fuel efficiency. This means this property can be analyzed accurately and in real-time without having to take the vehicle into a service or diagnostic station. The fuel efficiency, in turn, can characterize related problems with the vehicle, such as under-inflated tires or a clogged fuel-injection system. The host computer system also hosts an Internet-accessible website that can be viewed by the vehicle""s owner, his mechanic, or other parties. The web site also includes functionality to enhance the data being collected, e.g. it can be used to collect a different type of diagnostic data or the frequency at which the data are collected. Most ECUs do not directly calculate fuel efficiency. Thus, the system must collect data related to fuel efficiency and transmit it to the host computer system. This system, in turn, calculates fuel efficiency from these data as described in detail below.
In one aspect, the invention provides a method and device for characterizing a vehicle""s fuel efficiency and amount of fuel consumed. The method features the steps of: 1) generating data from the vehicle that can include vehicle speed, engine speed, load, mass air flow, and manifold air pressure; 2) transferring the data to a wireless appliance that includes i) a microprocessor, and ii) a wireless transmitter in electrical contact with the microprocessor; 3) transmitting a data packet comprising the data or properties calculated from the data with the wireless transmitter over an airlink to a host computer system; and 4) analyzing the data or properties calculated from the data with the host computer system to determine a vehicle""s fuel efficiency.
In embodiments, the generating and transferring steps are performed at a first time interval (e.g., about 20 seconds) and the transmitting and analyzing steps are performed at a second time interval (e.g., once a day).
The method typically includes the step of processing at least one of the following properties from the data set: vehicle speed, odometer calculation, engine speed, load, manifold air flow, and manifold air pressure. This is typically done following the transferring step. In this case, xe2x80x98processingxe2x80x99 typically includes summing or integrating at least one of the properties from the data set, or a property derived thereof, to yield a summed property. For example, the data parameters can be integrated with respect to the time interval that they are collected. The summed or integrated property is then multiplied by a time interval to complete the integration process. The microprocessor contained in the wireless appliance typically performs these steps prior to the transmitting step.
For example, an odometer calculation is typically not available from a vehicle""s ECU. It must therefore be calculated by querying the ECU at a relatively high frequency to determine the vehicle""s speed, and then assuming that the speed is constant between queries. With this assumption, the speed can be multiplied by the time between queries to determine the distance driven. This distance can then be summed and then transmitted to determine an odometer calculation. This method is described in more detail in the patent application entitled xe2x80x98WIRELESS DIAGNOSTIC SYSTEM FOR CHARACTERIZING MILEAGE, FUEL LEVEL, AND PERIOD OF OPERATION FOR ONE OR MORE VEHICLESxe2x80x99, U.S. Ser. No. 09/776,083, filed Feb. 1, 2001, the contents of which are incorporated by reference. A similar integration method can be applied to MAF, LOAD, and LOAD times RPM, as described in more detail below, to determine fuel consumed and fuel efficiency.
MAF is typically the integrated property, and the analyzing step further comprises processing the resulting data to determine an amount of fuel consumed. For example, the analyzing step can include: 1) dividing the integrated MAF by an air/fuel ratio; and 2) dividing the results from step 1) by a density of fuel to determine a volume of fuel consumed. The analyzing step further includes dividing the amount of fuel consumed by a distance driven to determine fuel efficiency.
In other embodiments, the integrated property is LOAD or LOAD times RPM, and the analyzing step further comprises processing the integrated value to determine an amount of fuel consumed. For example, the microprocessor can integrate LOAD or LOAD times RPM to generate a value that is then multiplied by a constant to determine an integrated, synthetic mass air flow. This property is then processed as described above to determine both an amount of fuel consumed and fuel efficiency. As described in more detail below, for some vehicles an integrated LOAD value correlates well with fuel efficiency, while in others it is an integrated LOAD times RPM that correlates.
In other embodiments, the analysis step further includes processing the vehicle""s fuel efficiency to determine a secondary property of the vehicle, e.g. tire pressure, status of a fuel-injection system, or fuel quality.
In still other embodiments, the method includes comparing the vehicle""s fuel efficiency to a pre-determined criteria (e.g., a recommended fuel efficiency). The method can also include a step where the vehicle""s fuel efficiency or a property derived from the fuel efficiency is sent to a user using, e.g. an electronic text, data, or voice message. This message can be sent to a computer, cellular telephone, or wireless device. The message can describe a status of the vehicle""s fuel efficiency or fuel consumption. The method can also include the step of displaying the data set and/or fuel efficiency on an Internet-accessible web site.
The method includes processing the data packet with the host computer system to retrieve the data set or a version thereof. In this case, a xe2x80x98version thereofxe2x80x99 means a representation (e.g. a binary or encrypted representation) of data in the data set that may not be exactly equivalent to the original data retrieved from the ECU. The data set or portions thereof are typically stored in a database comprised by the host computer system.
The wireless network can be a data network such Cingular""s Mobitex network, Motient""s DataTAC network, or Skytel""s Reflex network, or a conventional voice or cellular network. The wireless appliance typically operates in a 2-way mode, i.e. it can both send and receive data. For example, it can receive data that modifies the frequencies at which it sends out data packets or queries the ECU, or the data that it collects from the ECU. Such a wireless appliance is described in the application WIRELESS DIAGNOSTIC SYSTEM FOR VEHICLES, filed Feb. 1, 2001, the contents of which are incorporated herein by reference.
In the above-described method, the term xe2x80x98airlinkxe2x80x99 refers to a standard wireless connection (e.g., a connection used for wireless telephones or pagers) between a transmitter and a receiver. This term describes the connection between the wireless transmitter and the wireless network that supports data transmitted by this component. Also in the above-described method, the xe2x80x98generatingxe2x80x99 and xe2x80x98transmittingxe2x80x99 steps can be performed at any time and with any frequency, depending on the diagnoses being performed. For a xe2x80x98real-timexe2x80x99 diagnoses of a vehicle""s engine performance, for example, the steps may be performed at rapid time or mileage intervals (e.g., several times each minute, or every few miles). Alternatively, other diagnoses may require the steps to be performed only once each year or after a large number of miles are driven. Alternatively, the vehicle may be configured to automatically perform these steps at predetermined or random time intervals. As described in detail below, the transmission frequency can be changed in real time by downloading a new xe2x80x98schemaxe2x80x99 to the wireless appliance through the wireless network.
The term xe2x80x98emailxe2x80x99 as used herein refers to conventional electronic mail messages sent over a network, such as the Internet. The term xe2x80x98web pagexe2x80x99 refers to a standard, single graphical user interface or xe2x80x98pagexe2x80x99 that is hosted on the Internet or worldwide web. A xe2x80x98web sitexe2x80x99 typically includes multiple web pages, many of which are xe2x80x98linkedxe2x80x99 together and can be accessed through a series of xe2x80x98mouse clicksxe2x80x99. Web pages typically include: 1) a xe2x80x98graphicalxe2x80x99 component for displaying a user interface (typically written in a computer language called xe2x80x98HTMLxe2x80x99 or hypertext mark-up language); an xe2x80x98applicationxe2x80x99 component that produces functional applications, e.g. sorting and customer registration, for the graphical functions on the page (typically written in, e.g., C++ or java); and a database component that accesses a relational database (typically written in a database-specific language, e.g. SQL*Plus for Oracle databases).
The invention has many advantages. In particular, wireless, real-time transmission and analysis of data, followed by analysis and display of these data using a web site hosted on the Internet to determine a vehicle""s fuel efficiency or fuel consumption, makes it possible to characterize the vehicle""s performance in real-time from virtually any location that has Internet access, provided the vehicle being tested includes the above-described wireless appliance. Analysis of these data, coupled with analysis of transmitted diagnostic trouble codes, ultimately means that many problems associated with fuel efficiency can be quickly and efficiently diagnosed. When used to continuously monitor vehicles, the above-mentioned system can notify the vehicle""s owner precisely when the vehicle""s fuel efficiency falls below a user-defined pre-set level. In this way, problems that affect fuel efficiency, such as under-inflated tires, clogged fuel-injections systems, engine oil level, can be identified and subsequently repaired.
The wireless appliance used to access and transmit the vehicle""s data is small, low-cost, and can be easily installed in nearly every vehicle with an OBD-II connector in a matter of minutes. It can also be easily transferred from one vehicle to another, or easily replaced if it malfunctions. No additional wiring is required to install the appliance.
These and other advantages of the invention are described in the following detailed disclosure and in the claims.